The researchers noted that the food served in these 'big four' restaurants contain more than twice the recommended daily amount of salt for adults, and almost four times the limit for a six-year-old child.
Prof Graham MacGregor, the chairman of Cash and the director of St George's Hospital Medical School blood pressure department, said that using salt was a smart ploy as it is addictive. However, he also insisted that it can be harmful.
"Salt is very addictive. You see this in children when you give them good, home-cooked food without much salt, they think it does not taste right," The Telegraph quoted him, as saying. "The profit margins on a lot of the products are huge - cheap ingredients are often used and salt is put in, bringing the level up almost to the concentration of sea water.
"If you eat very salty foods, that suppresses the salt receptors on the tongue and increases demand for salty foods." The report however, was branded biased by the fast food chains. A spokesman for KFC and Pizza Hut said: "Every sensible parent knows that Pizza Hut and KFC are an enjoyable treat and we have significantly reduced the salt levels in our products over the past few years."
McDonald's and Burger King turned the findings around to say that it showed that the chains have worked hard to reduce their salt levels.